Titanium metal injection molding (Ti-MIM) has been practiced since the late 1980s.

With respect to titanium, this process has found use primarily in niche markets such as the manufacture of jewelry, cases for watches and portable electronics. While these applications take advantage of the high specific strength and excellent corrosion resistance of titanium, penetration of titanium MIM (Ti-MIM) products into the automotive, aerospace, chemical production, and biomedical market sectors has been limited because of historical problems with alloy impurities that are directly attributable to the injection molding process. Specifically, carbon, oxygen, and nitrogen are left behind during binder removal and become incorporated into the chemistry and microstructure of the material during densification. Even at low concentration, these impurities can cause severe degradation in the mechanical properties of titanium and its alloys. Thus, issues which are key to the acceptance of Ti-MIM components in advanced engineering applications are those that pertain to reducing these impurities to an acceptable minimum level in a cost-effective manner. They include:

(1) development of high purity titanium powder;

(2) design of a binder/solvent system that can be easily removed, does not require burn-out in an oxidizing environment, and leaves behind no residual carbon;

(3) subsequent development of a controlled method of sintering under a protective environment.

Pacific Northwest National Laboratory (PNNL) is currently investigating low cost methods of manufacturing high purity Ti powder and at PNNL Battelle is investigating new techniques for fabricating high quality components from these and other powders.

Logically, the Ti-MIM practice follows the similar processes developed for the antecedent materials such as stainless steel and ceramics. Although Ti-MIM is a favorite research topic today, the issue of convincing the designers to use Ti injection-molded parts still exists. This is mainly because of the concern about contamination which seems unavoidable during the Ti-MIM process. Much information about the binder formulation, powder requirements, debinding, and sintering is available in the literature. There are several powder vendors and feedstock suppliers. However, most of the binders in the feedstock are proprietarily protected. The disclosed information on the binders used for formulating powder feedstock is very limited, which in turn discourages their adoption by engineering designers.